Switching to calendar view simply crashes with the following error message
printed in the console:

GThread-ERROR **: file gthread-posix.c: line 351 (): error 'Cannot allocate
memory' during 'pthread_create'

Using the exchange connector.  Earlier the calendar worked fine, then all
of the sudden it just started crashing.  The first crash occurred right
after creating a new task, but since then any attempt to switch to calendar
crashes.

The stack trace indicates evolution ends up creating new threads in an
endless loop until around 256 threads it just crashes.